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//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later
// version.
//
// This library is distributed in the hope that it will be
// useful, but WITHOUT ANY WARRANTY; without even the implied
// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
// PURPOSE. See the GNU Lesser General Public License for more
// details.
//
// You should have received a copy of the GNU Lesser General
// Public License along with this library; if not, write to the
//
// Free Software Foundation, Inc.,
// 59 Temple Place, Suite 330,
// Boston, MA
// 02111-1307 USA
//
// The Initial Developer of the Original Code is Charles W. Rapp.
// Portions created by Charles W. Rapp are
// Copyright 2012, 2013, 2016, 2019, 2020. Charles W. Rapp
// All Rights Reserved.
//

package net.sf.eBusx.monitor;

import java.io.Serializable;
import java.util.Formatter;
import net.sf.eBus.messages.ENotificationMessage;

/**
 * Reports the {@link Monitor#register(Monitorable) registration}
 * or {@link Monitor#deregister(Monitorable) deregistration} or
 * a {@link Monitorable} instance. The {@link #instance} field
 * contains the monitored object unique identifier and
 * {@link #updateFlag} is {@code true} if the object registered
 * and {@code false} if the object deregistered.
 * 
 * In order to receive this notification message, subscribe to:
 * {@code net.sf.eBusx.monitor.MonitorUpdate}:{@link Monitor#MONITOR_UPDATE_SUBJECT}.
 *
 * @see ApplicationInfo
 * @see Monitor
 *
 * @author Charles Rapp
 */

public final class MonitorUpdate
    extends ENotificationMessage
    implements Serializable
{

//---------------------------------------------------------------
// Member data.
//

    //-----------------------------------------------------------
    // Constants.
    //

    /**
     * Serialization version identifier.
     */
    private static final long serialVersionUID = 0x050200L;

    //-----------------------------------------------------------
    // Locals.
    //

    /**
     * This monitored object was either added or removed.
     */
    public final MonitorId instance;

    /**
     * {@code true} if added and {@code false} if removed.
     */
    public final boolean updateFlag;

//---------------------------------------------------------------
// Member methods.
//

    //-----------------------------------------------------------
    // Constructors.
    //

    /**
     * Creates a new MonitorUpdate instance for the given
     * instance and flag.
     * @param subject the notification subject.
     * @param inst the updated monitored instance.
     * @param flag the update type.
     * @exception IllegalArgumentException
     * if {@code inst} is {@code null}.
     */
    @Deprecated
    public MonitorUpdate(final String subject,
                         final MonitorId inst,
                         final boolean flag)
        throws IllegalArgumentException
    {
        this (subject,
              System.currentTimeMillis(),
              inst,
              flag);
    } // end of MonitorUpdate(String, MonitorId, boolean)

    /**
     * Deserialization constructor.
     * @param subject the notification subject.
     * @param timestamp the message timestamp.
     * @param inst updated instance.
     * @param flag update type.
     * @exception IllegalArgumentException
     * if {@code inst} is {@code null}.
     */
    @Deprecated
    public MonitorUpdate(final String subject,
                         final long timestamp,
                         final MonitorId inst,
                         final boolean flag)
        throws IllegalArgumentException
    {
        super (subject, timestamp);

        if (inst == null)
        {
            throw (new IllegalArgumentException("null inst"));
        }

        instance = inst;
        updateFlag = flag;
    } // end of MonitorUpdate(String, long, MonitorId, boolean)

    private MonitorUpdate(final Builder builder)
    {
        super (builder);

        this.instance = builder.mInstance;
        this.updateFlag = builder.mUpdateFlag;
    } // end of MonitorUpdate(Builder)

    //
    // end of Constructors.
    //-----------------------------------------------------------

    //-----------------------------------------------------------
    // Object Method Overrides.
    //

    @Override
    public String toString()
    {
        final Formatter retval = new Formatter();

        retval.format("%s%n               instance: %s%n",
                      super.toString(),
                      instance);
        retval.format("                 update: %b",
                      updateFlag);

        return (retval.toString());
    } // end of toString()

    //
    // end of Object Method Overrides.
    //-----------------------------------------------------------

    public static Builder builder()
    {
        return (new Builder());
    } // end of builder()

//---------------------------------------------------------------
// Inner classes.
//

    public static final class Builder
        extends ENotificationMessage.Builder
    {
    //-----------------------------------------------------------
    // Member data.
    //

        //-------------------------------------------------------
        // Locals.
        //

        private MonitorId mInstance;
        private boolean mUpdateFlag;

    //-----------------------------------------------------------
    // Member methods.
    //

        //-------------------------------------------------------
        // Constructors.
        //

        private Builder()
        {
            super (MonitorUpdate.class);

            this.subject(Monitor.MONITOR_UPDATE_SUBJECT);
        } // end of Builder()

        //
        // end of Constructors.
        //-------------------------------------------------------

        //-------------------------------------------------------
        // Builder Method Overrides.
        //

        @Override
        protected MonitorUpdate buildImpl()
        {
            return (new MonitorUpdate(this));
        } // end of buildImpl()

        @Override
        protected Validator validate(final Validator problems)
        {
            return (super.validate(problems)
                         .requireNotNull(mInstance, "instance"));
        } // end of validate(Validator)

        //
        // end of Builder Method Overrides.
        //-------------------------------------------------------

        //-------------------------------------------------------
        // Set Methods.
        //

        public Builder instance(final MonitorId id)
        {
            if (id == null)
            {
                throw (new NullPointerException("id is null"));
            }

            mInstance = id;

            return (this);
        } // end of instance(MonitorId)

        public Builder updateFlag(final boolean flag)
        {
            mUpdateFlag = flag;

            return (this);
        } // end of updateFlag(boolean)

        //
        // end of Set Methods.
        //-------------------------------------------------------
    } // end of class Builder
} // end of class MonitorUpdate